Experimental Insight into the Small Strains Behaviour of Compacted Clay

This study presents the results of an experimental investigation into the stress-strain behaviour of re-compacted unsaturated clayey soil, with an emphasis on the behaviour at small strains levels. Series of triaxial tests were conducted in a hydraulic stress path controlled cell, on unconsolidated undrained samples. No measurement of pore water pressure was made; the results were interpreted in terms of total stresses. To account for the small strains behaviour of the soil, several strains measurement methods were used. Initially identical isotropicaly compressed specimens were subjected to triaxial compression following a variety of stress paths. The strains measurements, the stress path dependency and the effect of the initial isotropic confining pressure are discussed. For the interpretation of the results obtained, use was made of the method of strains energy contours.